Sudden Acquired Retinal Degeneration (SARDS)

What is SARDS? SARDS is a condition seen in dogs which usually results in a rapid degeneration of the retina leading to irreversible, complete vision loss over a few days to a few weeks. The retina usually appears normal when initially examined because the degeneration occurs so rapidly. Over at least several months, the retina will eventually begin to show evidence of degeneration upon examination.

CauseThe cause of SARDS is unknown at this time. It has been shown that it is not an inherited (genetic) disorder. It is currently thought that it is a toxic reaction in the retina possibly related to fat bi-products, hormonal or immune-mediated causes.

Typical ScenarioThe disease normally occurs in middle-age to older dogs who are commonly overweight. Female dogs are affected more often than male dogs. SARDS may occur in any breed including mixed breed dogs; however, of the purebred dogs, dachshunds and schnauzers appear to be overrepresented. The disease is sometimes associated with an increase in thirst, urination and weight gain. SARDS may be associated with Cushing’s disease, a condition associated with overproduction of corticosteroids by the adrenal gland. If symptoms are suggestive of Cushing’s disease, blood testing is recommended.

DiagnosisSARDS is usually confirmed by performing an electrical function test of the retina called an electroretinogram (ERG). Since the retina appears normal on initial evaluation, the ERG is essential to distinguish SARDS from other causes of blindness including central nervous system disorders of the optic nerve or the brain. If a dog has SARDS, the ERG will show an absence of retinal activity. If the retinal activity is normal, then the reason for vision loss is within the brain or optic nerve. In such cases additional diagnostic testing and/or consultation with a neurologist may be recommended to determine the cause of the blindness.

Treatment and expectationsThis is a non-painful condition that causes permanent blindness. In pets that are positive for Cushing’s disease, treatment for Cushing’s is recommended because this disease can have adverse effects on other body systems. Unfortunately, treatment of Cushing’s disease will not improve vision.

Adjusting to SARDSBecause pets with SARDS have rapid vision loss, adjustment to their home environment takes several weeks. Dogs’ strong sense of smell, memory and hearing are important during their adaptive period.

For more information on this subject, speak to the veterinarian who is treating your pet.